Aviation helmet



FIG. 1 is a left side-elevational view of the aviation helmet, showing the new design;

FIG. 2 is a right side-elevational view of the aviation helmet;

FIG. 3 is a front view;

FIG. 4 is a rear view;

FIG. 5 is a top view;

FIG. 6 is a bottom view; and,

FIG. 7 is a left side isometric view thereof.

The broken lines in the figures illustrate portions of the aviation helmet that form no part of the claimed design. 

CLAIM I claim the ornamental design for an aviation helmet, as shown and described. 